Quantitative Extraction of p-Coumaric Acid and Ferulic Acid in Different Gramineous Materials and Structural Changes of Residual Alkali Lignin

Ferulic acid(FA)and p-coumaric acid(pCA)in bagasse,wheat straw,corn straw,and corncob were extracted by alkaline hydrolysis and characterized by gas chromatography(GC)and gas chromatography-mass spectrometry(GC-MS).It was found that the FA and most of the pCA in gramineous biomass could be dissociated and released after being treated with 1 M NaOH at 100℃for 4 h.The yields of pCA/FA in bagasse,wheat straw,corn straw,and corncob determined by GC-FID are 39.8/11.5,13.7/11.0,28.0/11.0,and 35.1/14.5 mg/g,respectively.The raw materials and the treated solid residues were characterized by gel-state 2D Heteronuclear Single Quantum Coherence Nuclear Magnetic Resonance(2D HSQC NMR).It was found that only a small amount of lignin was detected in the residue after alkali treatment,indicating that the alkali treatment conditions can effectively cleave the FA and pCA.Additionally,the lignin in the alkali solution was recovered and characterized by 2D HSQC NMR.The FA was not able to be detected by NMR,whereas a small amount of pCA remained in the alkali lignin.This study reveals the structural change of residual lignins during the quantitative isolation of FA and pCA,which is essential for the selective isolation of pCA/FA and valorization of residual alkali lignin.

Events associated with apoptotic effect of p-Coumaric acid in HCT-15 colon cancer cells

AIM:To investigate the events associated with the apoptotic effect of p-Coumaric acid,one of the phenolic components of honey,in human colorectal carcinoma(HCT-15)cells.METHODS:3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltertazolium-bromide assay was performed to determine the antiproliferative effect of p-Coumaric acid against colon cancer cells.Colony forming assay was conducted to quantify the colony inhibition in HCT15 and HT 29 colon cancer cells after p-Coumaric acid treatment.Propidium Iodide staining of the HCT15 cells using flow cytometry was done to study the changes in the cell cycle of treated cells.Identification of apoptosis was done using scanning electron microscope and photomicrograph evaluation of HCT 15cells after exposing to p-Coumaric acid.Levels of reactive oxygen species(ROS)of HCT 15 cells exposed to p-Coumaric acid was evaluated using 2’,7’-dichlorfluorescein-diacetate.Mitochondrial membrane potential of HCT-15 was assessed using rhodamine-123 with the help of flow cytometry.Lipid layer breaks associated with p-Coumaric acid treatment was quantified using the dye merocyanine 540.Apoptosis was confirmed and quantified using flow cytometric analysis of HCT15 cells subjected to p-Coumaric acid treatment after staining with YO-PRO-1.RESULTS:Antiproliferative test showed p-Coumaric acid has an inhibitory effect on HCT 15 and HT 29 cells with an IC50(concentration for 50%inhibition)value of 1400 and 1600μmol/L respectively.Colony forming assay revealed the time-dependent inhibition of HCT 15 and HT 29 cells subjected to p-Coumaric acid treatment.Propidium iodide staining of treated HCT 15cells showed increasing accumulation of apoptotic cells(37.45±1.98 vs 1.07±1.01)at sub-G1phase of the cell cycle after p-Coumaric acid treatment.HCT-15 cells observed with photomicrograph and scanning electron microscope showed the signs of apoptosis like blebbing and shrinkage after p-Coumaric acid exposure.Evaluation of the lipid layer showed increasing lipid layer breaks was associated with the growth inhibition of p-Coumaric acid.A fall in mitochondrial membrane potential and increasing ROS generation was observed in the p-Coumaric acid treated cells.Further apoptosis evaluated by YO-PRO-1 staining also showed the timedependent increase of apoptotic cells after treatment.CONCLUSION:These results depicted that p-Coumaric acid inhibited the growth of colon cancer cells by inducing apoptosis through ROS-mitochondrial pathway.

非共价/共价相互作用对明胶-PCA复合物功能特性和稳定性的影响

为探讨原儿茶酸(protocatechuic acid,PCA)与明胶之间的相互作用对明胶-PCA复合物功能特性和稳定性的影响,本文通过非共价和共价结合方式制备明胶-PCA复合物,采用紫外-可见光谱、荧光光谱和傅里叶红外光谱分析PCA与明胶之间的相互作用,并对复合物的抗氧化活性、抑菌活性和稳定性进行分析。结果表明,与非共价复合物相比,共价复合物具有更高的PCA结合率。PCA与明胶二者相互作用对明胶具有荧光淬灭作用,且共价作用引起的荧光淬灭程度更大。明胶-PCA复合物具有优异1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基和2,2'-联氮-双-3-乙基苯并噻唑啉-6-磺酸(2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid,ABTS+)自由基清除能力。与共价复合物GPCA-2相比,非共价复合物GPCA-1对DPPH和ABTS+自由基清除能力更加显著(P<0.05),其清除率分别为49.71%±2.9%和38.39%±0.57%。明胶-PCA复合物还表现出对大肠杆菌、李斯特菌和沙门氏菌的抑菌作用。与GPCA-2相比,GPCA-1的抑菌效果更加显著(P<0.05),其大肠杆菌、李斯特菌和沙门氏菌的抑菌圈直径分别为11.31±0.91、12.57±0.93和8.83±0.35 mm。虽然PCA与明胶之间的相互作用在一定程度上降低了PCA的抗氧化活性和抑菌活性,却能显著(P<0.05)提高PCA的光稳定性和热稳定性。明胶-PCA共价复合物在紫外光和热处理80 min后,其PCA的保留率可达到92.58%±0.62%和90.30%±0.97%。实验结果为功能型明胶-PCA复合产品的开发与利用提供理论依据。

p-Coumaric acid ameliorates ethanol-induced kidney injury by inhibiting inflammatory cytokine production and NF-κB signaling in rats

Objective: To examine the effects of p-coumaric acid on ethanol-induced kidney injury in Swiss Wistar rats.Methods: Ethanol(25% v/v) was used to induce nephrotoxicity in rats. p-Coumaric acid was orally administered at 50, 100, or 200 mg/kg body weight. The levels of oxidative parameters were determined; pro-inflammatory biomarkers were analyzed by Western blotting and apoptotic protein was analyzed by immunohistochemistry. Results: Ethanol treated rats showed decreased levels of antioxidants and aberrant production of pro-inflammatory cytokines(IL-6, IL1β, TNF-α), NF-κB activation and imbalance of proand anti-apoptotic proteins(Bcl-2, Bax, caspase 3). Meanwhile, p-coumaric acid restored antioxidant levels and decreased the levels of inflammatory cytokines, NF-κB, and proapoptotic proteins and increased Bcl-2 expression. Conclusions: p-Coumaric acid ameliorates ethanol-induced kidney injury by restoring antioxidant production and suppressing cellular apoptosis and inhibiting NF-κB expression.p-Coumaric acid should be further investigated as a promising candidate for ethanol-induced kidney toxicity.

p-Coumaric acid alleviates adriamycin-induced hepatotoxicity in rats

Objective:To evaluate the effect of p-coumaric acid against adriamycin-induced hepatotoxicity in rats.Methods:The rats were divided into 4 groups.The control group received solvent;the p-coumaric acid group was treated with 100 mg/kg of p-coumaric acid orally for five consecutive days;the adriamycin group was administered with a single dose of adriamycin(15 mg/kg,i.p.),and the p-coumaric acid+adriamycin group was given p-coumaric acid five days before adriamycin administration.Twenty-four hours after the last administration,blood samples were collected for biochemical analysis,and liver tissues were removed for histopathological and immunohistochemistrical studies.Moreover,the levels of tissue lipid peroxidation and enzyme activities of glutathione peroxidase,superoxide dismutase,and catalase in liver tissue were measured.Results:Treatment with p-coumaric acid protected the liver from the toxicity of adriamycin by attenuating the increase in alkaline phosphatase,alanine transaminase,aspartate transaminase,total bilirubin,total cholesterol,triglyceride,and low-density lipoprotein cholesterol and lessening the decrease in high-density lipoprotein cholesterol and albumin.p-Coumaric acid also raised the levels of glutathione peroxidase,superoxide dismutase,and catalase,as well as decreased lipid peroxidation in liver tissue and hepatic IL-1βexpression.Additionally,histopathological study confirmed the protective effect of p-coumaric acid against liver damage.Conclusions:p-Coumaric acid can alleviate adriamycin-induced hepatotoxicity.

Simultaneous determination of gallic acid and p-coumaric acid in rat plasma by UPLC-MS/MS and its application to a comparative pharmacokinetic study after oral administration of monomer compound and red wine extract

A rapid,sensitive and selective ultra high performance liquid chromatography-tandem mass spectrometry(UPLCMS/MS)method was developed and validated for simultaneous determination of gallic acid(GA)and p-coumaric acid(CA)in rat plasma.Plasma samples were extracted by methanol and separated on an ACQUITY UPLC BEH C18 column(1.7μm,100 mm×2.1 mm)using gradient elution consisting of acetonitrile–0.2%formic acid within a runtime of 4.0 min.The detection was performed in multiple reaction monitoring(MRM)mode with negative ionization.The linear range was 20–20000 ng/mL for both GA and CA,with lower limits of quantification of 20 ng/mL.Intra-day and inter-day precisions were within 5.4%and 10.0%,respectively and the accuracy(relative error,RE,%)was less than 7.2%and–4.9%,respectively.The mean absolute extraction recoveries of both analytes and IS from rat plasma were all more than 82.6%.The validated method was successfully applied to the comparative pharmacokinetic study of GA and CA in rat plasma after oral administration of GA and CA monomers and red wine extract,respectively.It was found that both the area under the curve(AUC)and t1/2 of the two constituents were remarkably increased for red wine extract group than that in monomer group,indicating the priority of intake of red wine to active component monomer.

基于脂肪酸组成结合主成分分析识别不同比例大豆油和菜籽油调配的调和油

结合脂肪酸组成和化学计量学方法,对大豆油、菜籽油及其不同比例的二元调和油的识别进行基础研究,并分析不同比例调和油中脂肪酸含量的变化。结果表明在大豆油和菜籽油中,共检出脂肪酸组分17种,主要以油酸、亚油酸、棕榈酸和亚麻酸为主。在以不同比例低芥酸菜籽油和大豆油调配的调和油中,脂肪酸含量随调和比例的改变而呈现一定趋势的增加或减小。结合脂肪酸组成,对所有的139个样品进行了主成分分析(PCA),结果表明大豆油和菜籽油可以互相实现区分,不同比例的调和油样品分布在调配的溯源样品之间,基本按照比例关系分布成一条直线。研究通过对菜籽油、大豆油及其不同比例调配的调和油的脂肪酸组成进行了定量分析,分析了它们之间脂肪酸组成的变化,并结合化学计量学手段进行一些识别分析,为规范调和油的生产和保障公平有序的调和油市场提供参考。

原儿茶酸促进铁循环强化Fenton体系降解避蚊胺

为了减少传统Fenton体系中Fe(Ⅱ)的投加量,提高H_(2)O_(2)的利用率,选择添加原儿茶酸(PCA)实现Fenton体系中的铁循环。以避蚊胺(DEET)为目标污染物,在最佳反应条件:c(DEET)0=0.2 mmol/L,c(H_(2)O_(2))=1.0 mmol/L,n(H_(2)O_(2))/n[Fe(Ⅱ)]=20∶1,n(PCA)/n[Fe(Ⅱ)]=1∶1,pH值=3.0下,DEET在20 min内降解率可达75%。对DEET降解过程中的总铁(TFe)和Fe(Ⅱ)浓度的变化进行记录,证明了PCA除了作为络合剂提高溶液中Fe离子的溶解度,也可作为还原剂促进体系中的Fe循环。利用叔丁醇(TBA)和对苯醌(PBQ)作为自由基淬灭剂鉴别反应体系中主要活性物质,得出PCA/Fe(Ⅱ)/H_(2)O_(2)体系中起主要氧化作用的是羟基自由基(·OH)。共存离子试验结果表明,SO^(2-)_(4)的存在对DEET的降解没有影响。对常见的污染物降解试验表明,Fe(Ⅱ)/PCA/H_(2)O_(2)体系普适性较好。

诱变筛选荧光假单胞菌M18高产吩嗪-1-羧酸(PCA)菌株及发酵条件研究

研究了亚硝基胍 (NTG)的诱变剂量、处理时间以及氯化钠浓度对野生型荧光假单胞菌M 18存活率的影响 ,NTG的诱变剂量 2 5～ 2 0 0mg/L ,处理时间 10～ 30min范围内 ,随着诱变剂剂量增加和时间的延长 ,M 18的存活率不断下降。NTG的作用剂量 2 5mg/L ,处理时间 10min时 ,细菌存活率为 5 5 %左右。利用细菌存活率为 5 5 %时的诱变条件 ,经生物测定 ,初筛获得 2 0株抑菌效果明显的诱变株。经摇瓶发酵复筛 ,从这 2 0株诱变株中 ,获得PCA高产诱变株M 18N0 7。并对此菌株发酵条件进行调整 ,较理想的培养条件为 :蛋白胨 18g/L ,葡萄糖 16 g/L ,氯化钠 1g/L ,硝酸钾10 g/L。小瓶培养时间 17h ,大瓶 5 %接种量 ,2 8℃培养 5 4h。

用pH—pCa电极对直接测定土壤的石灰位

石灰位定义为pH—0.5pCa。与pH值相比较,石灰位能更全面地反映土壤的酸性强度。讨论了用pH玻璃电极和PVC膜钙电极(以ETH1001为载体)测定石灰位的原理和方法。研究了土壤中的含盐量、氧化铁、有机质以及水土比对土壤石灰位测定的影响。给出了中国黄壤、黄棕壤、红壤和砖红壤的旱地及水稻土的石灰位的测定结果。根据大量的实验结果,对我国南方主要酸性土壤的酸性强度作了分级。

基于PCA-ANN组合学习方法建立PTA粒度模型

针对在精对苯二甲酸(PTA)生产过程中影响PTA粒度的因素多且复杂,采用了主元分析方法(PCA)提取方差最大的几个成分作为神经网络(ANN)的输入,消除干扰因素的影响,建立PCA ANN粒度模型。为了进一步提高PCA ANN粒度模型的预测精度,提出了性能优良的加权组合学习方法,形成基于PCA ANN的加权组合模型。组合模型能通过对多个不同PCA ANN粒度模型的预测结果进行自适应加权,最终获得具有良好预测精度的结果。

产PCA基因工程菌M18G反复补料分批培养研究

吩嗪-1-羧酸(PCA)是一种广谱、高效的微生物源农药,采用反复补料分批培养工艺可提高PCA合成速率,为实现PCA的商业化生产打下了良好的基础。本试验针对高产PCA的基因工程菌M18G,首先在摇瓶培养条件下,用正交试验法研究了培养基中各主要营养因子葡萄糖、黄豆粉、甘油、95%乙醇等对PCA产量的影响,并确定了适合PCA分泌的最佳培养基(1L)为:葡萄糖6g,黄豆粉40g,甘油6mL,95%乙醇5.9mL;然后确定了反复补料分批培养时更换新鲜培养基的最佳时间为每次培养进行48h后、体积比例为90%。在此条件下,培养进行五个周期后,PCA的合成速率可达到2.27mg/h,是优化后分批培养的1.34倍,同时延长了培养周期,有利于提高设备使用率,降低生产成本。

Induced Effects of Exogenous Phenolic Acids on Allelopathy of a Wild Rice Accession(Oryza longistaminata,S37)

Four exogenous phenolic acids, including salicylic acid, fumalic acid, p-coumaric acid and p-hydroxybenzonic acid, were used to investigate the regulatory effects on allelopathy of a wild rice accession of S37 （Oryza Iongistaminata）, which is a known allelopathic rice. The four exogenous phenolic acids induced the enhancement of the allelopathic potential of wild rice S37 in target weeds though the weed-suppressive activities were low, and the inducible effects were dependent on the specific phenolic acid, concentration and treatment time. After foliar application of exogenous phenolic acids, the inhibition rates for plant height, root length and fresh weight of barnyard grass （Echinochioa crus-galli） were significantly higher than those of the control. Especially at the concentration of 100 mg/L, the inhibition rates for plant height and fresh weight of barnyard grass by fumalic acid were 38.12% and 26.31% higher than those of the control, showing that fumalic acid was more effective compared with other phenolic acids in inhibiting monocotyledon weed growth. Furthermore, the weedsuppressive activity of aqueous extract from the leaves of wild rice S37 treated with exogenous phenolic acids was increased, and it peaked at 48 h after the treatment with the aqueous extract, and then gradually declined.

Changes of chlorogenic acid content and its synthesis-associated genes expression in Xuehua pear fruit during development

According to synthetic pathway of plant chlorogenic acid （CGA）, the expression patterns of genes encoding enzymes that are associated with CGA synthesis were studied in normally developed Xuehua pear fruit. The study demonstrated that CGA content in peel and flesh of Xuehua pear decreased as fruit development progressed, with a higher level in peel. The expression levels of PbPAL 1, PbPAL2, PbC3H, PbC4H, Pb4CL 1, Pb4CL2, Pb4CL6, PbHC T1 and PbHC T3 genes decreased in fruit, which was consistent with the pattern of variation in CGA content. That indicated that these genes might be key genes for influencing fruit CGA synthesis in Xuehua pear. However, Pb4CL7 gene expression profile is not consistent with variation of CGA content, hence, it may not be a key gene involved in CGA synthesis.

Acidity Regimes of Soils Under Different Vegetations in the Changbai Mountains Region

The acidity regimes of representative soils on the north slope of the Changbai Mountains were examined through determinations of PH and pCa of the soil paste as well as in-site determinations. For soils under broad-leaf forest or broad-leaf-Korean pine forest, the pH decreased from the litter to lower layers gradually until it did not change or decreased further slightly. For soils under coniferous forest or Ermans birch forest,there was a minimum in pH at a depth of 3～6 cm where the content of humus was high. The pCa increased gradually from the soil surface downward to a constant value. The lime potential (pH-0.5pCa) showed a similar trend as the PH in its distribution. For a given soil, the measured pH value of the thick paste, ranging from 4.5 to 5.5, was lower by about 0.5 units than the value determined by the conventional method with a water to soil ratio of 5:1. The PH determined in site was even lower. It was found that there was a fairly close relationship between soil acidity and the type of vegetation. The pH showed a trend of decreasing from soils under broad-leaf forest through broad-leaf-conifer mixed forest and coniferous forest to Ermans birch forest, and the pCa showed an opposite trend in variation.

基于GC-MS及PCA对比15种奶酪的有机酸成分

为明确不同加工工艺对奶酪有机酸物质的影响,该试验采用液液萃取-气相色谱-质谱联用技术(liquid liquid extraction-gas chromatography-mass spectrometer,LLE-GC-MS)研究传统奶豆腐、西式奶酪及再制奶酪共15种奶酪有机酸成分的差异。结果显示:传统奶豆腐制作过程中基本不添加其它物质且未经过成熟工序,有机酸成分较少且含量不高,主要有机酸包括乙酸、己酸、癸酸、十二酸、十四酸、十六酸、壬酸、9-癸烯酸;西式奶酪制作过程中会添加高脂肪物质,经过成熟处理,有机酸成分明显增加,主要有机酸包括己酸、辛酸、癸酸、十二酸、十四酸、十六酸、壬酸、9-癸烯酸;再制奶酪因原料包括成品奶酪及其它营养物质,其有机酸成分是三类奶酪中最多的一类,主要有机酸包括苯甲酸、丁酸、己酸、辛酸、癸酸、十二酸、十四酸、十六酸、十八酸、十五酸、9-癸烯酸、9-十六碳烯酸。三类奶酪都含有己酸、癸酸、十二酸、十四酸、十六酸、9-癸烯酸,其中双碳酸较多。主成分分析可用于区分传统奶豆腐及再制奶酪,对不同工艺西式奶酪的区分并不理想。

基于PCA-RBF层叠泛化网络的硝酸生产工艺历史数据建模

硝酸工业对国民经济、国防工业的发展起着重要的支持作用,而成品酸流量是硝酸生产过程重要的技术指标。提出了一种基于层叠泛化策略的成品酸流量的预测建模方法。首先,用主成分分析(PCA)对原始数据降维,提取前5个主成分作为影响因子集合;然后,构建两级RBF网络学习层,第一级针对影响因子空间,对一组RBF神经网络进行交互验证式训练得到输出值和对应的真实值所组成的的特征空间;第二级由单个RBF网络将第一级网络得到的特征空间进行非线性组合;最后,将模型用于预测出口成品酸流量,并与相应实测值进行比较以验证其合理性。结果表明,本文建立的层叠泛化网络模型具有较高的预测精度和泛化性能,对于硝酸生产工艺的分析和优化具有显著的指导意义。

蒸汽爆破处理对金针菇菇脚游离氨基酸及挥发性风味成分的影响

采用蒸汽爆破的方式对金针菇菇脚进行预处理,探究蒸汽爆破对金针菇菇脚游离氨基酸及挥发性风味成分的影响,基于气相色谱-离子迁移谱技术对蒸汽爆破前后金针菇菇脚挥发性风味成分进行分析,采用氨基酸分析仪测定蒸汽爆破前后金针菇菇脚中游离氨基酸的组成及含量。结果表明,在蒸汽爆破前后金针菇菇脚中共鉴定出33种挥发性成分,包括11种酯类、7种醛类、3种吡嗪类、2种酸类、2种醇类、2种酮类、1种醚类、1种烯烃类。同时,采用Gallery Plot指纹图谱和动态主成分分析,探究蒸汽爆破对金针菇菇脚挥发性物质的影响,研究表明,蒸汽爆破前后挥发性成分种类及含量存在较大差异。蒸汽爆破处理后,游离氨基酸含量和必需氨基酸含量增加,且谷氨酸的相对含量明显升高,是未汽爆处理的1.52倍。因此,蒸汽爆破技术可以作为一种新型食用菌废弃物预处理技术,促进金针菇废弃物高值利用,值得进一步深入研究。

基于顶空固相微萃取-气相色谱-质谱联用法、电子鼻和电子舌技术分析绿茶饮料的风味物质

[目的]本文旨在分析绿茶饮料中的特征挥发性和非挥发性化合物,为绿茶饮料风味质量评价提供科学参考。[方法]利用顶空固相微萃取-气相色谱-质谱联用仪(headspace solid phase micro-extraction gas chromatography mass spectrometry,HS-SPME/GC-MS)和电子鼻技术,对12种绿茶饮料的挥发性风味物质进行测定,并结合电子舌和全自动氨基酸分析仪对绿茶饮料中的非挥发性成分进行比较。[结果]利用HS-SPME/GC-MS在12种绿茶饮料中共检测出135种香气物质,其中酯类40种,醇类21种,醛酮类27种,萜烯类31种,烃类8种,酚类4种,酸类1种,其他物质3种。共有的挥发性香气组分是柠檬烯、α-松油醇和芳樟醇,根据气味活度值(odour activity value,OAV)确定芳樟醇是绿茶饮料的特征香气物质,挥发性物质种类和含量赋予绿茶饮料独特的风味。主成分分析(principal component analysis,PCA)结果表明电子鼻和电子舌可以区分12种绿茶饮料,第一主成分(PC1)与第二主成分(PC2)的贡献率之和分别达91.08%和92.58%。茶氨酸是绿茶饮料中含量最高的游离氨基酸,茶氨酸含量与绿茶饮料整体滋味呈显著正相关(P<0.05)。[结论]不同种类绿茶饮料的气味和滋味特征存在差异,通过HS-SPME/GC-MS、电子鼻、电子舌和氨基酸分析技术相结合的手段,可以较好地分析12种绿茶饮料中的风味物质。

不同干燥条件对风干牛肉品质影响

为提高风干牛肉的干燥效率,明确干燥条件对风干牛肉品质的影响,以牛肉为研究对象,通过常规方式和高温短时干燥处理方式[对照组(15℃,7 d)、A组(50℃,30 h)、B组(55℃,27 h)、C组(60℃,24 h)、D组(65℃,21 h)]对其进行风干,分析不同处理对牛肉水分含量、水分活度、剪切力、蛋白质氧化、硫代巴比妥酸反应物(thiobarbituric acid reactive substances,TBARS)值、游离氨基酸含量、风味成分变化及感官评分的影响。结果表明,高温短时干燥对风干牛肉水分含量和水分活度影响不显著(p>0.05),对牛肉剪切力影响显著(p<0.05)。风干牛肉脂肪氧化和蛋白质的氧化、水解随着风干温度升高而增加。风干结束后,5组样品中TBARS值最高为1.18 mg MDA/kg,羰基含量为4.66 mmol/mg蛋白;风干牛肉游离氨基酸总量B组最高,为628.88 mg/100 g。气相色谱-离子迁移谱(gas chromatography ion mobility spectrometry,GC-IMS)结果显示,B组样品主要的挥发性风味物质最为丰富,且与其他4组差异最大,主要的特征风味物质为丁酸丙酯、丙二酸二乙酯、辛酸乙酯、丙酸异丁酯、乙酸甲酯、乙酸正己酯、乙酸辛酯等;适当提高干燥温度可以明显改善风干牛肉的色泽、风味和组织状态的评分。综合各项指标,风干温度55℃、风干时间27 h处理的风干牛肉品质最佳。